Retroperitoneal perforation of the appendix presenting as subcutaneous emphysema of the thigh.

Retroperitoneal abscesses may develop insidiously, resulting in delayed diagnosis with significant morbidity and mortality. Subcutaneous emphysema of the thigh may be a late manifestation of this process, and often heralds a poor prognosis because of associated myonecrosis and fulminant sepsis. The presentation and clinical course of such a patient is summarized, and the relevant anatomy of the retroperitoneal spaces that predisposes to this condition is described.